纳米碳酸钙合成研究

采用传统的鼓泡碳化法，用50℃热水快速消化石灰，精制石灰乳冷却到20℃以下碳化，制备纳米碳酸钙。研究了碳化过程中粘度和pH的变化，以及陈化和添加晶形控制剂对纳米碳酸钙晶形的影响。通过陈化一二次碳化法制备了晶形比较完整的纳米碳酸钙，从而降低了纳米碳酸钙的吸油量。通过添加不同的晶形控制剂，可以制备立方体形、立方柱形、棒状和菱形纳米碳酸钙。     

纳米碳酸钙的制备及表面改性技术

综述了纳米碳酸钙的制备方法及其表面改性技术,并对纳米碳酸钙的发展前景进行了展望。纳米碳酸钙的制备分为碳化法和复分解法两类,其中碳化法可分为间歇鼓泡碳化法、连续喷雾碳化法和超重力碳化法三种。纳米碳酸钙的表面改性技术目前主要有有机物表面处理、高能表面处理和无机物改性三种方法。     

纳米碳酸钙的制备技术与表面改性方法

简述了我国纳米碳酸钙技术发展现状。介绍了纳米碳酸钙的生产技术路线,探讨了其中的碳化工艺和表面改性方法。目前我国有鼓泡碳化、喷雾碳化和超重力碳化等的碳化工艺,可采用钛酸酯、铝酸酯等偶联剂和脂肪酸、磷酸酯等表面活性剂对纳米碳酸钙进行表面改性。     

纳米碳酸钙生产工艺及其超重力法优越性

较为系统地叙述了目前工业上生产纳米碳酸钙的方法。对一步碳化法、两步碳化法、多段喷雾碳化法、超重力旋转填充床碳化法制备纳米碳酸钙材料的方法进行了比较和总结，并阐述了超重力技术的基本原理及其优越性。     

纳米碳酸钙制备技术评述

简要介绍了纳米碳酸钙的制备方法和碳化法的碳化机理，详细介绍了纳米CaCO3的制备新技术，为生产高性价比的纳米CaCO3产品提供了新途径。     

电石渣制备立方体晶型纳米碳酸钙研究

以电石渣为原料制备纳米碳酸钙,考察了水、氯化铵、添加剂用量、氨水用量和碳化温度对纳米碳酸钙产品的影响,用XRD、BET和SEM等分析手段进行了产品质量表征.SEM和XRD图表明,低温碳化有利于纳米碳酸钙的生成,且形成比较规则的立方体晶型,纳米碳酸钙产品尺度为30～80nm.     

多级喷雾碳化法制备纳米碳酸钙工艺研究

研究了多级喷雾碳化制备纳米碳酸钙的工艺,并详细讨论了雾化、碳化条件及添加剂量等对纳米碳酸钙粒径的影响,碳化后的沉淀物真空干燥,其原始粒径约为30nm。经表面改性处理,可得到粒径在30－40nm范围的活性纳米碳酸钙粉体材料。     

电石渣制备立方体晶型纳米碳酸钙研究

以电石渣为原料制备纳米碳酸钙,考察了水、氯化铵、添加剂用量、氨水用量和碳化温度对纳米碳酸钙产品的影响,用XRD、BET和SEM等分析手段进行了产品质量表征.SEM和XRD图表明,低温碳化有利于纳米碳酸钙的生成,且形成比较规则的立方体晶型,纳米碳酸钙产品尺度为30～80nm.     

纳米碳酸钙引进技术中多级鼓泡碳化工艺探讨

对引进的日本、意大利及中国台湾的纳米碳酸钙生产工艺中的碳化技术进行对比，反映出多级鼓泡碳化与单一间歇鼓泡碳化在工艺、设备及控制等方面的差异，从而决定了产品在应用中的差异。为降低生产成本，实现常温碳化制备纳米碳酸钙，晶核预成技术在工业化生产中得到了广泛的应用，并不断完善。指出企业应根据全套生产装置特点对产品的应用方向做出选择。     

纳米级碳酸钙的生产、应用和开发前景

介绍了纳米级碳酸钙的4种生产方法:多段喷雾碳化法、一步碳化法、二步碳化法和旋转填充床碳化器碳化法。阐述了纳米级碳酸钙在橡胶、塑料制品、造纸、涂料、油墨等方面的应用情况及其开发前景。     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。